Painting of gas holders



Oct. 12, 1948. L. B. DONOVAN PAINTING OF GAS HOLDERS 4 Sheets-Sheet 1 Filed March 50, 1945 INVENTOR. Lew/s 5 Don 0 m/v ATTO/P/VA'YS Oct. 12, 1948. L. B. DONOVAN 2,451,158

PAINTING 0F GAS HOLDERS Filed March so, 1945 4 Sheets-Sheet 2 Oct. 12, 1948. 1 DONOVAN 2,451,158

PAINTING OF GAS HOLDERS Filed March 30, 1945 4 Sheets-Sheet 3 30 32 50 INVENTOR.

/ 51405 5 Don/0144 1 Tia-.7- ZMM A TTO/P/VEY5 Oct. 12, 1948.

L. B. DONOVAN PAINTING OF GAS HOLDERS Filed uar'cn so, 1945 4 Sheets-Sheet 4 W LI Patented Oct. 12, 1948 PAINTING OF GAS HOLDERS Lewis B. Donovan, White Plains, N. Y., assignor to Consolidated Edison Company of New York, Inc., New York, N. Y., a corporation of New York Application March 30, 1945, Serial No. 585,609

4 Claims.

This invention relates to the painting of gasholders and particularly to the painting of the major portions of the outer or exposed surfaces of the movable sections of a telescoping watersealed gas-holder.

In the maintenance of telescoping gas-holders, the painting of their outer exposed surfaces presents serious problems owing to the large areas of these surfaces, the large amount of labor required for doing the painting by the usual methods, and the hazards to the workmen doing the paintin owing to the elevations at and the conditions under which they must work. In some climates, deterioration of the surface coatings of gas-holders is so rapid that frequent renewal of the surface coatings is required, a fact which makes highly important all of the factors just mentioned.

The general object of the present invention is to provide for economical painting of the major portions of the outside surfaces of gas-holders having one or more lifts or movable sections provided at their bottoms with water-seals.

The method of the present invention is broadly Characterized by the delivery of a layer of floatlng paint on the water-seal of each lift or telescoping section of the gas-holder, followed by progressive lowering and raising of said telescop in sections, whereby paint is drawn first downwardly and then upwardly from said floating paint layers on to the outside surfaces of the various telescoping sections, after which the surplus paint left floating on the surfaces of the various Water-seals is removed for subsequent use.

An apparatus suitable for practicing the methon of the present invention is described and claimed in my application Serial No. 661,670, filed May 12, 1946. for Painting apparatus which is a continuation-in-part of the present application. It is to be understood, however, that the method of the present invention may be practiced with other apparatus.

By the term paint, as used in this specification and the appended claims, is meant any suitable surface coating such as paint, drying oil, etc. The paint to be used must be suitable not only for coating the surfaces to be covered but also for use in accordance with the present invention. The specific gravity of the paint preferably should be less than the specific gravity of water, in order that it may float on the surface of the water-seals which are provided at the bottom of each section of the gas-holder. For best results a paint should be chosen having a viscosity as well as a specific gravity within certain limits as hereinafter explained. Also, the paint used. should not easily emulsify with water or, if a paint is used which does emulsify with water, it should be easily recoverable from the emulsion. In the practice of the present invention, a larger quantity of paint is required than would be used for covering the equivalent surface in ordinary ways such as by brushing or spraying; but surplus paint employed according to the present invention may be recovered for use again, as will be obvious from the following description of the method and an apparatus which may be employed in practicing the invention.

The invention will be understood from the following description taken in connection with the accompanying drawings schematically illustrating both the method and a form of apparatus for carrying it out. In the drawings, Fig. 1 is a. fragmentary sectional-elevation of a gas-holder of conventional type, in the position which it assumes when completely filled with gas so that its sections are in their uppermost position, the paint being shown as having been applied in a floating layer to the water-seal of the bottom section; Fig. 2 is a fragmentary sectional-elevation similar to Fig. 1 showing the two lower sections of the gas-holder in lowered position and the next section about to be lowered, during the painting operation; Fig. 3 is a sectional-elevation showing all of the sections of the gas-holder in their lowered positions during the painting operi ation; Fig. 4 is a sectional-elevation showing the upper three sections of the gas-holder, after they have been elevated during the paintin operation; Fig. 5 is a fragmentary sectional-elevation, on a scale larger than Figs. 1 to 4, showing the manner in which the surplus paint drains back from the surface of a gas-holder section on to the water-seal from which it had been drawn; Fig. 6 is a plan view, which is somewhat diagrammatic, showing the distribution piping extending around the gas-holder and communicating with those places to and from which paint is to be delivered and removed during the painting operation; Figs. *7 and 7a are elevations showing respectively two forms of skimming devices useful for removing the surplus paint from the waterseals; Figs. 8 and 8a are plan views of the devices shown in Figs. '7 and 7a respectively; and Fig. 9 is a sectional and partly conventional elevation showing apparatus (which is preferably mounted on a truck to make it portable) useful in the painting of the outside surfaces of the movable lift or lifts of a water-sealed gas-holder in accordance with the present invention.

, holder telescope as the amount of gas in the holder decreases. The foundation 9 is filled with Water to a predetermined level, as indicated in Figs. 1 to 5. For convenience of reference, the various sections of the gaseholder-are indicated in the drawings by referenoe'charact ers A, B, C, D and E. Each of these sections is provided at its bottom with a water-seal of a well known type of construction such as diagrammatically illus trated in the drawings. hese water-seals act in a manner well understood to prevent the escape of gas from the inside of the gas-holder, regardlessrofathepositions to which the sections of the gas-fholdermay be velevatedor lowered under the influence of varying quantities ofgas within the holder." These water-seals :are utilized in carrying out the painting operation according to "the present invention in the manner which will now baa-described.

When allisections A to E of the gas-holder are to rbe painted, -suflicient;-gas :is pumped into the gas-"holder to fully extend its=telescoping sections to the;po'siti-ons in-dioated in Fig. l. Thena layer of :floatin'gz paint isdelivered as shown at e to thewater-seal at the bottom of section E; after which enough gas is withdrawn fro'mthe gas-holder to permit section it to sink into the water-filled foundation :9 nearly to its lowermost position.

Duringthe'sinkingof section paint from the floating paint layer e adheres to the dry outside surface of section E, and vis :drawn downwardly from :the floating paint layer-e, as indicated at Pin-Figs; 2.;and;3. Section D (and also sections C, :B and 5A) of the gas-holder have then sunk untilrtheiwatenseal of section Dis approximatelyiat the level of the top of the foundation '9;

whereupon ia l-ayer:drotfloating paint is supplied to the water-seal of sectionzD. Then more'gas is withdrawn from the gas-holder; until section E3SlIlk S toits lowermost position in the foundation i9,-'and section D-gsink nearly to its lowermost aposition. During thesesinkings of sections E and D,;pa=int is drawn-downwardly from the paint layers 'e and d of the water-sealsat "the bottomsof-sections Eand *Dgon to'the previously dry outer-surface of "those sections as indicated at :P in Fig. -2. Then thecoperations just describedare repeate'd for-se'ctions C,=B,and. A, until all of the sections of the egas holder are in;=the position shown in Fig. 3, which shows themajor portions of the outside surfaces of the movable sections .A to of 'the gas-holder coated at P with paint athathas been drawn downwardly from the .paint layers a, 'b, 0, id ande floating on the surfaces of :the various water-seals oi the sections to During the lowering f the gashol'der .sections, "satisfactory adhesion of the paint-coatings .P to "the previously dry surfaces: of the 'seotion'takes placaiithe pa t is selected. as :one having a suitable viscosity and specific gravity, .andthis adhesion is not disturbed by submersion of those p-aint-ooated'portion's in the water within the foundationill.

:Ailter-the gas-holder sections A,-B, 0,13 and E havezsunk to the positions shown in Fig. 3, suffici'entgas ispumped-into the gas-holder :to raise section A until thenooperating par-tsiorming the 4 water-seal between sections A and B are in the position illustrated in Fig. 5. During the rising of section A, paint from the floating paint layer a on the water-seal is drawn upwardly on to the. already paint-coated surface of section A. thereby adding another paint-coating, the two paint-:ccatings being indicated at P in Fig. 5

a (and 81180311 Fig. .4 Where :paint has been twice applied to sections A, B and C). Fig. 5 shows -fho.W the surplus paint which has been drawn upwardlyfrom the floating paint layer a drains'baok intothat'floating paint layer. Owing to the slow upward;mov;en'i-ent-of section A, this drainage of surplus ipaint back into the floating paint layer dis largely completed by the time section A has finished its first stage of upward movement. Then or soon thereafter, .all of the paint left in the floating paint layer a is removed by the use of the apparatus hereinafter described or by any other suitable means.

l hereaiter, sufiic'ient additional ,gas is pumped into the gas-holder toraise sectionA and with'it seetionB untilthecooperating partsiorming the water-seal'between sectionsB and Care at, a level slightly above the top of the foundations. During this upward movementofsection B, thelsurplus paint :-which has :been drawn upwardly from the floating paintlayer bon to the previousl paint-coveredsurfaoeof section B, drains back into the floating paint layer 17'. Then or soon pain-t layer b-is removed in the manner hereinbeiore mentioned. .The operations ,just described are successively-repeated by the successive pumping of gas into the gas holderthereby causing the ftions when :the "painting operations have been partiallyeompleted, that is, the sections A and Bryhfii-VG been v:t-wice coated iwith paint at P and the surplus paint has-beenremovedirom the surfaces-oi the water-seals for those sections; sec-o tion-Cqhasbeen twice-c'oated withpaint at P' -but the sur-plus paint has not yetbeen removedgfrom the water-seal;and-sections D-xand-E have been once-coated'with paint :at Pduring their downward movement into thew-ater contained in the ifoundation fi. It will be noted that the introductionofzthe various-paint layers on tothe surfaces of the various water-seals, and-the removal of the surpluspaint from those water-seals, takes place at a level-onlyrslightl-y above-the top of the foun- ;dation :9. 'Therefore,-the paint distributionpiping and parts associated therewith, for the introduction of the floating paint layers and the removaloi 'thesurplus paint, may the arranged at thesame'low level around theoutside of the gas- ,holder. This is one of :theimportant advantages of ithe invention, since-the *workmenhandling the introduction of paint into and the removal of paint irom the various water-seals can work around :the gasholder at s'onelow level. Sinoeit desirable to removethe surplus paint from the water-seals as-soon as possible, the removal 0peration maybe commenced without awaiting the completion'of-alloi' thedrainage of surplus paint from-;the-surfaces of the gas-'holderisections. By Eso-prQceediHg-thetimeerequired for the complete paintingioperationcan be kept .to a minimum.

EIf desired, it will'loe understood that the gasholder-may be painted one'lift or section at a time, or, for example, twoliftsa't a time. In such cases it-ispreferableiltostart with ithe upper :lift or the thereafter, allsof the paint .left in the floating upper two lifts so that these may, in their uppermost positions, have ample time for the paint to dry, while the lower sections are raised or lowered for painting or in normal use.

In order to secure the most desirable results, care should be taken in selecting a paint which not only has a specific gravity low enough to float on the water, but it also appears desirable to take into consideration the relationship of the specific gravity to the viscosity of the paint used. In general it appears desirable to avoid use of paints which are relatively thin and have a high specific gravity, even though the specific gravity is less than that of water. It would appear that paints having a specific gravity within the range of about 0.80 to 0.99 with a preferred gravity of about 0.91 are most satisfactory for the purposes of the invention if so chosen that the viscosity thereof will be within a range of about 25 to 60 seconds (as measured in Consolidated Edison Company #4 Ford type cup at 70 F.)

While a variety of difierent kinds of paint may be used for the purpose, care should also be taken to select one in which the pigments and other ingredients do not tend to stratify in the paint layer within the period of time required for conducting the painting operations on a gas holder. Paints embodying carbon black and having gravities and viscosities within the above stated limits have been found satisfactory, also aluminum paints of such viscosity or other characteristics as will cause the aluminum particles to be maintained in suspension for the requisite period. Paints of various colors are also available for the purpose.

Since for good results the viscosity of the paint as applied is important, and since the viscosity ma be substantiall higher at winter temperatures, than during the summer, it will be apparent that in selecting a paint of proper viscosity, one should take into consideration the outdoor temperature at which the paint is to be used for the purpose. As above indicated the paint should also be one which does not readily emulsify when being pumped along with water through the particular pump being used.

The apparatus illustrated in Figs. 6 to 9 for supplying paint to the water-seals, for removing surplus paint therefrom, and for de-watering the removed paint, will now be described. It is desirable that the paint be distributed to the various water-seals at a plurality of points around the gas holder, so that a floating paint layer which is substantially uniform in depth will be produced. Also. in removing the surplus paint from the water-seals it is desirable that the removal be effected at a plurality of places in the waterseals around the gas-holder, to facilitate complete removal of the surplus paint as quickly as possi ble. To these ends, distribution piping may be arranged around the gas-holder slightly above the level at which the treatments of the waterseals are to take place, that is slightly above the top of the foundation 9, as hereinbefore described,

An example of such distribution piping is illustrated in Fig. 6. Such piping and its arrangement may of course be varied depending upon the form and dimensions of the gas-holder. In this figure, the distribution piping is shown as comprising pipes I5 connected to one another at their ends by flexible connections I6 and branch pipes I 8 extending with flexible connections to the places in the water-seals to which paint is to be delivered and from which paint is to be removed. Each of these branch pipes I8 is preferably provided with a valve 20 for controlling the flow of paint to and from the water-seal via that pipe; and these branch pipes l8 are adapted to be attached to skimming nozzles of any suitable kind such as the one shown in Figs. 7 and 8 and hereinafter described. One of the pipes I5 is provided with a feed pipe 22 leading to the apparatus (a form of which is shown in Fig. 9 and hereinafter described) by which the paint is supplied to and withdrawn from the water-seals through thedistribution piping. Valves 24 and 26 may be inserted in the pipe I5 at each side of the place to which the pipe 22 is connected, to facilitate the feeding and withdrawal of paint.

Figs. 7 and 8 show a skimming nozzle 30 attached to a pipe 32 which may be connected to a pipe l8 by hose connections (not shown) or in any other suitable manner. A simpler form of skimming nozzle is shown in Figs. 7a and 8a, comprising a pipe 32' with its lower end portion bent in to a horizontal position and formed with a slot as at 30' adapted to be placed in a position to extend along just below the surface of the paint to be removed. The distribution piping and the skimming nozzles may be supported from the stationary frames around the gas-holder, in any suitable manner. If desired, the skimming nozzles may be employed not only for removing the surplus paint from the water-seals but also for supplying the paint in a floating layer on the surface of the water-seals.

Fig. 9 shows a form of apparatus useful for supplying paint through the pipe 22 to the distribution piping, the nozzles and the various water-seals, and for removing the surplus paint and for de-watering it. This apparatus is preferably mounted on a truck so as to be readily portable. As shown in Fig. 9, the apparatus includes a pump diagrammatically indicated at 34 which may be driven from any convenient source of power; and a paint holding tank divided into sections 36, 38, 40, 42 and 44 by partitions 45 upwardly extendin from the tank bottom 46 nearly to the top of the tank, as shown in the drawing. In the top of the tank above each tank section is an opening 48 having a cover 56, through which paint may be introduced into the various tank sections. As shown in Fig, 9, the bottom of each tank section 36, 38, 40, 42 and 44 is connected by a pipe 52 containing a valve 53 to a common pipe or bottom header 54. The bottom of each tank section is also provided with a test valve 56 in a pipe 51 which communicates with the tank section, for purposes hereinafter described. The top of each tank section 36, 38, 40, 42 and 44 is connected by a pipe 66 containing a valve 6| to a common pipe or top header 62. The direction of flow through the pump 34 is indicated by the arrows on the intake and outlet sides of the pump. As will be obvious from Fig. 9, the intake side of the pump is connected with the bottom header 54 through a pipe 64 and a valve 65, and with the distribution piping 22 through a valve 66 and a pipe 61. It will also be noted that the outlet side of the pump 34 is connected with the top header 62 through a valve 68; and that the outlet side of the pump 34 is also connected to the distribution piping 22 through a pipe 69 and a valve 16.

The manner in which the several valves may be manipulated so as to selectively control the pumping of paint from the bottom of any tank section 36, 38, 40, 42 and 44 to the distribution piping 22, or from the distribution piping 22 to the top of any tank section, or from the bottom of any tank section to the top of any tank section, will now be described.

Let it :be assumed that painthas ibeen {intro-- 7 duced'into all of the tank sections '35, 38, :40, 42

to shut off connection of the pump 34 with the topheader 62; the intake side of the pump 34 is connected to the bottomheader 54 by opening the valve 65; the valve 56 isclosedin order to cut-off the intake side of the pump 34 from connection with the pipe 22; .and the valve 12 nearthe end of the bottom header 54;isc1osed, as is-also a'valve 8| which may be provided inza pipe 86 'fora'purpose later explained. Opening of "any one or more-of the valves 53 will permit paint to flow fromeany one or .more of the-tank sections "-36, :38, 40,42 and into the bottom header54. Therefore, with the valves set'in the manner .just de-'- scribed, thepump 34-=will draw paint from any one or more of the tanksections through'one or more of ;th'e,pipes 52 into the bottom header 54, the

valve -65 and the pipe @64 and-the pump will vforce 1 paint from its outlet through'the pipe-69 and valve 10 andto thepipe 22 leading to the distri bution piping arranged around .thegas-hold'er. Obviously,the supply of paint to the distribution piping may be controlled by'manipulation of the valves 24 and 2,6 in the distribution piping, and by the valve 10 which is part of the apparatus showninFig. 9.

:Letdtbe-assumed that the :painting of a gasholder section :has been completed, .and'that it isdesired to'withdraw thesurplus paint from'the water-seal. Let it also be assumed thatthe :distribution piping and the skimming -'devices ."have been suitably arranged around the gas-holder preparatory to the paint-removing operation. The va1vesi65, -1il'-and'-8 l are closed and the-valve 66is ,open, thereby'connecting the intakesideof the pump 34 (through .thepipe '64," valve E6 and pipe 61) 'withthe pipe 22 leading to the distribution piping; and :the valve 68 and any one or more. of the valves-6i are opentherebyconnecting the outlet side of the pump :(through the valve 68, .top header '62, pipe or pipes I53 and valve or valves 3|) :to the top of one or -:more-of thetank'sections 36, 38, 40, 42 and44. Under open .valve 68 and pipe 64, 1 and .dBliVEIS this paint through the open .valve 68'and'topheader :52 .to one or-moreof the tank-sections through thepipe orpipes fiflin which the valve or valves fil 'zare open. The operation of removingsurplus paint from-the water-seal may obviously be controlled bymanipulation of the valves 23, 24 and 26 inzthe distribution pipin-g,and by lmanipulation of the valve fit which is part of the apparatus shownin Fig; 9.

In the withdrawing of surplus paint from the water-eseals, somewateris' likely alsoto be withdrawnandileft mingled with the paintinone or more *of the tank-sections. .Ihe mannerin which the apparatus shown in t-Fig. v9 may be used ,for the storage amide-watering of such paint will now :be described. Letis be'assumed' that enough paint and water have been withdrawn from' -a water-seal into the tank sections 33 and 38 to are empty. The :paint and water in the tank:

sections 36 and 38 will stratify into a top paint layer and a bottom water layer, since the paint is of less specific gravity than the water and does not emulsify with the water. The existence of thebottom'w-ater layers can-be proved by opening the test Valves :56. in the pipes 51 extending into the bottoms .of the tank sections. permissible to discharge water from ,the'tank'sections at the place'where the truck carrying'the apparatus-shown in Fig. 9 is located, the water in the bottom layers in tank sections 38 and :38

maybe drained outlthrough the pipes 52, valves 53, bottom header pipe 54and the valve 12; valves 65 andiil, andathe Valves 53 beneath tank sec charge the water in the bottom layers in tank,

sections 36 and 38, that water may be pumped from those sections into empty tank section 44 whereit may betemporarily stored. During this water-pumping operation, :the valves 53 beneath] the tanksections 33 and .38 are open, and the 'valves 53 beneath the tank sections '40, 42 and and-valve 12 are closed, valve55 is open, valves, 56, H3 and .8 are closed, valve :68is open and all of the valves 65 above the varioustank-sections are closed except valve 6! above tank'section-44 'which is open.

Instead of the procedures just described, all of the water and paint in section 236 may :be pumped out of that section into tank section 38 thereby not only filling that section but causing floating paint to flow from that section 38 into section 40 overthe toprof the :partition between.

sired to use the-pipe 80, valves 55,58 and are L closedand valves fifiand 8! opened. Then with the pump operating,-paint willbedrawnzfrompipe 22 through valve- 66 inpipe blthroughthe pump, and forced through valve 8| .in pipe 80 into headeripipe 54, thence through anyof the valves 53as'desired,into'the bottomportionof one or more of .the tank sections.

In these and other ways the paint and water maybe separated and stored in the 'various'tank sections. When, however, itis possible to discharge the water at the place where the apparatus shown .in Fig. .9 is located, that procedure is preferableto .thepumpingof water fromuone tank section toanother. It will be obvious also thatthe apparatus shown in Fig. -9 permits the pumping of paint from any tank section to any other tank section. .Andof coursethemethodof painting gas-holder'sections which is herein 'described and claimed *may be carried outwith many formsof apparatus other than i'that'shown in Fig. "9. 7

While the'invention'has been described in *detail with respect to-certain preferred examples,

without departing .from the spirit and "scope of.

If it is the invention, and it is intended therefore in the appended claims to cover all such changes and modifications.

What is claimed as new and desired to be secured by Letters Patent is:

1. Method for painting the exterior wall surfaces of a gas holder of a type having a plurality of telescoping sections, each provided with a water seal adjacent its lower edge and adapted to be raised and lowered by gas compressing and exhausting equipment cooperating with the holder, which method comprises the following steps starting with the sections in elevated position and with their external surfaces substantially dry: first delivering a layer of floating paint onto the water seal for a lower section, exhausting sufficient gas to lower the sections whereby paint is drawn from such water seal onto the outside dry wall surfaces of said lower section, delivering a layer of such paint onto the water seal for a higher section, exhausting suflicient gas whereby such higher section is lowered and paint is drawn from the last named water seal onto the outside dry wall surfaces of such higher section, thereafter introducing sufiicient compressed gas to elevate such higher section whereby paint is again drawn onto the outside surface thereof, then removing the excess paint from the last named water seal, thereafter further introducing suflicient compressed gas to elevate said lower section whereby another layer of paint from the first named water seal is drawn onto the outside surface of such lower section, and finally removing excess paint from the first named water seal.

2. Method for painting the exterior wall surfaces of a gas holder of a type havin a plurality of telescoping sections, each provided with a water seal adjacent its lower edge and adapted to be raised and lowered by gas compressing and exhausting equipment cooperating with the holder, which method comprises the following steps starting with the uppermost section only in elevated position and dry on its outer surface: first delivering a layer of floating paint onto the water seal for said uppermost section, exhausting sufficient gas to lower such section, whereby paint is drawn from such water seal onto the outside wall surface of said uppermost section, introducing sufiicient compressed gas to then elevate said uppermost section and also removing the excess paint from the water seal and elevatin another section, delivering a layer of such paint onto the water seal for such other section, and causing paint to be drawn onto such other section in the same manner as for the uppermost section.

3. Method for painting the exterior wall surfaces of a movable section of a gas holder provided with a water seal adjacent its lower edge and adapted to be raised and lowered by gas compressing and exhausting equipment cooperating with the holder, which method comprises delivering floating paint onto the water seal simultaneously at a plurality of spaced points around the holder to rapidly form' a layer of paint of substantially uniform thickness on the water, operating said equipment to vertically move the section whereby paint is drawn from the water seal onto said wall surfaces of the section, and then skimming off the excess paint promptly and before same becomes dried from the water seal simultaneously at a plurality of spaced points around the section.

4. Method for painting the exterior wall surfaces of a gas holder of a. type having a plurality of telescoping sections, each provided with a water seal adjacent its lower edge and adapted to be raised and lowered by gas compressing and exhausting equipment cooperating with the holder, which method comprises the following steps starting with the sections in elevated position and with their external surfaces substantially dry; first delivering a layer of floating paint onto the water seal for a lower section, exhausting suflicient gas to lower the sections whereby paint is drawn from such water seal onto the outside dry wall surfaces of said lower section and the water seal for a higher section is brought down to a position adjacent a water seal for said lower section, delivering a. layer of such paint onto the Water seal for said higher section, then exhausting sufiicient gas whereby such higher section is lowered and paint is drawn from the water seal therefor onto the outside dry wall surfaces of such higher section, and removin excess paint from said water seals before such paint becomes dried.

LEWIS B. DQ-NOVAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,850,700 Taylor Mar. 22, 1932 1,911,124 Linder et al. May 23, 1933 1,949,234 Baxter Feb. 27, 1934 FOREIGN PATENTS Number Country Date 651,659 Germany Mar. 15, 1935 OTHER REFERENCES Meade, Modern Gasworks Practice, 2nd, ed., Pub. 1921 in London by Benn Bros. Ltd. Pages 672-673. 

